In the 115 years since it was founded, Tulsa, Okla.-based Doerner, Saunders, Daniel & Anderson has proven itself a regional powerhouse through the long-term relationships forged with its clients. It’s these strong ties that bolster the 42-lawyer firm’s vitality both throughout the state and beyond its borders.

Wayne Cooper, head of the transactional practice group at Doerner Saunders, said the recent national attention on natural gas as an alternative to petroleum has boosted business for many of its clients.

The firm has represented Tulsa’s own Heritage Propane in the company’s critical acquisitions. Their partnership, Cooper said, started in the 1990s and continues to be a source of mergers and acquisitions activity for the firm to this day. “Our firm has experienced a significant increase in M&A activity over the past few years, primarily in the energy sector,” Cooper said.

The firm also represents a family-owned company selling off properties in Pennsylvania that contain Marcellus Shale. While Cooper said he couldn’t disclose the name of the company, he did say it was selling off the properties because of state taxes. The proximity of the Marcellus Shale to many East Coast cities has increased its commodity value as states seek out alternate sources of energy.

Cooper also said the firm has a client he refers to as the “Cadillac of convenience stores” based in northeast Oklahoma. He said the bulk of locations are consolidated in the Midwest, but the company is expanding its locations through an increasing number of mergers and acquisitions, particularly in the Phoenix and Atlanta areas.

The firm has also seen an increase in business from Native Americans, largely driven by the gaming industry in the state. Tribes have used the firm as they seek to diversify. The firm has negotiated joint ventures with water plants, cattle operations and propane companies.

Doerner Saunders represented the Public Service Co. of Oklahoma, which was acquired in 1997 by American Electric Power as a wholly owned subsidiary — serving 527,000 customers throughout the state. The firm continues to be the primary firm for the company’s Oklahoma dealings.

The firm has also represented Fannie Mae in commercial foreclosures, but not transactional matters.

Cooper said the small size of the firm allows it to keep costs down — lower than many of his competitors in Dallas or Houston. “I believe the success we have enjoyed in the transactional area — and in fact all practice areas of the firm — is primarily due to our firm’s service-driven culture,” Cooper said. “We pride ourselves in providing the best possible legal service at a reasonable price.”

Matthew Huisman can be contacted at mhuisman@alm.com.